Re: 9i streams vs triggers

You may be right. I knew Oracle was different, but it looks like I need to get up to speed.

BTW, I searched for "MULTIVERSIONING." and got no hits. I'll keep looking.

"DA Morgan" <damorgan_at_exesolutions.com> wrote in message news:3E1EFA12.C88758AE_at_exesolutions.com...
> servant wrote:
>
> > Sybrand,
> >
> > I am having trouble understanding how I can design my database to have
data
> > that is updated and selected simultaneously without contention. The
update
> > will lock the row and block the select and vice versa, right? Can you
> > expand . . .?
> >
> > What I meant by replication is logical hot standby so I think we agree
> > there. That solves the contention issue but does not address the
complexity
> > issue. I agree that this is not a pretty solution, but I need a way to
take
> > the data from one data model, massage it with existing code (so I don't
have
> > to develop/maintain it in two places), and write it to another
"reporting"
> > database at near real time. Those requirements don't leave me with any
> > pretty solutions that I can think of. I am no guru, though, so I
certainly
> > welcome any suggestions.
> >
> > RAC, as I understand it, will give me scalability which, again, solves
the
> > performance/contention issue but does not address the complexity issue.
> >
> > You mentioned "Advanced Replication". I need to find out what that is
(I am
> > new to Oracle but learning fast). If it can call Java methods it just
might
> > work. Can you offer opinions on this versus triggers or streams?
> >
> > I'm off to tahiti (.oracle.com) . . .
> >
> > "Sybrand Bakker" <gooiditweg_at_nospam.demon.nl> wrote in message
> > news:77pr1v42q0kef48ad29cacqjvsinbqp6vl_at_4ax.com...
> > > On Thu, 9 Jan 2003 13:06:43 -0600, "servant" <mjohns1_at_uhc.com> wrote:
> > >
> > > >I have been tasked with developing a reporting architecture for an
> > > >application that has been developed over the last few months. I have
> > been
> > > >told there are 2 main concerns: performance (contention) and
complexity
> > of
> > > >the data model. I am thinking of using Oracle's replication to
maintain
> > a
> > > >(near) real-time replica. That (basically) resolves the contention
> > issue.
> > > >The complexity issue is more difficult.
> > > >
> > > >I am thinking about using 1) streams against the redo logs or 2)
triggers
> > to
> > > >pull the data from the replica, apply business logic to it, and
populate
> > a
> > > >"logical" data model on which reports can be generated. I would like
to
> > use
> > > >the same abstraction layer to go from the physical to the logical
data
> > model
> > > >as the application interface uses (Java objects with EJBs). In other
> > words,
> > > >I need the code inside the streams or triggers to call Java methods
(ie:
> > > >loadCustomerData(cust_id)) which would get the data and apply any
> > business
> > > >logic and then populate the "logical" database.
> > > >
> > > >In essence, I think I am being asked to create a data warehouse, but
I
> > > >haven't convinced myself of that yet.
> > > >
> > > >Anyway, here is my question: Does anyone have an opinion on which
method
> > > >(streams or triggers) would tax my replica database more--from a CPU,
> > > >network, and/or contention perspective? Any opinions from other
> > > >perspectives which option is better (maintenance, etc).
> > > >
> > > >
> > >
> > > First of all I would like to question the need of a replica database
> > > for reporting purposes. As for contention, this is simply not an
> > > issue, if the application has been designed properly. Your post has a
> > > distinct smell of finding a 'hardware solution' read 'workaround' for
> > > what is in reality a software design problem.
> > > If you really think you need a hardware solution you could just as
> > > well consider RAC, to have multiple servers running on the same
> > > instance.
> > > As for your option 1) you seem to be trying to re-invent the standby
> > > database technology . One simple advice: don't. You would never get it
> > > work, and provided your organisation has still a bag of $$ floating
> > > arond: get Oracle Enterprise Edition, set up a standby database which
> > > will use the redolog to keep the standby database up-to-date and start
> > > living
> > > As for your option 2) this seems like yet another solution which is
> > > going to be designed in a bike-shed. Replication can be accomplished
> > > by setting up the Advanced Replication option, and designing
> > > 'home-grown' solutions will definitely make you bald sooner and cost
> > > more.
> > >
> > > Regards
> > >
> > >
> > > Sybrand Bakker, Senior Oracle DBA
> > >
> > > To reply remove -verwijderdit from my e-mail address
>
> When you write: "I am having trouble understanding how I can design my
database
> to have data
> that is updated and selected simultaneously without contention." it leads
me to
> think that you are
> completely unaware of Oracle architecture.
>
> In Oracle reads don't block writes and writes don't block reads. If you
are
> designing, or your
> architect is designing based on knowledge of some other RDBMS it is time
to
> stop work on head
> for the Oracle concepts and architecture documentation.
>
> Daniel Morgan
>
Received on Fri Jan 10 2003 - 12:02:00 CST